Is THHN rated for wet locations?

[zappy]

Or does it have to have the #2 next to it. Meaning THHN-2? I'm asking because, you can only put 8-#8awg THHW wires in a 1" but THHN you can put 9. Thank you.

 

[nakulak]

see table 310.13

thhn is usally dual rated thhn/thwn. thwn is rated wet or dry

for the -2 see the note 4 at end of table.

 

[480sparky]

310.8
(C) Wet Locations. Insulated conductors and cables used in wet locations shall comply with one of the following:
(1) Be moisture-impervious metal-sheathed
(2) Be types MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, ZW
(3) Be of a type listed for use in wet locations.

 

[ActionDave]

All the wire that I have is labeled THHN/THWN.
I never look at the fill for anything other than THHN.

 

[zappy]

All the wire that I have is labeled THHN/THWN.
I never look at the fill for anything other than THHN.

Ok that's what I thought. Now if you use it in a wet loc. do you have to use the THWN colum, which is 75 degrees, for derating?

 

[ActionDave]

If you have the 2 like nakulak said then you can use the 90c column.
Derating is a pain when you get above 10AWG.

 

[480sparky]

Ok that's what I thought. Now if you use it in a wet loc. do you have to use the THWN colum, which is 75 degrees, for derating?

Yepper! .

 

[ItsHot]

submerged!

submerged!

I would hope so! I see a lot of it "submerged" in the back of trucks!!

 

[One-eyed Jack]

Ok that's what I thought. Now if you use it in a wet loc. do you have to use the THWN colum, which is 75 degrees, for derating?

You can use the 90 degree chart for derating . This would be your maximum load current. OCP would be determined by type of load served .

 

[infinity]

Ok that's what I thought. Now if you use it in a wet loc. do you have to use the THWN colum, which is 75 degrees, for derating?

You can use the 90 degree chart for derating . This would be your maximum load current. OCP would be determined by type of load served .

THHN/THWN is only rated for 75 degrees in wet locations so the derating would need to begin at the 75 degree ampacity. THWN-2 could be derated from the 90 degree ampacity.